Effect Of Annealing On The Hardness Of Cold Worked Al-6'1/Ocu Alloy

ABSTRACT

Effect of annealing temperatures and annealing time on the hardness of engineering materials is of great importance which needs c1·itical considerations. This work involves casting Al-6% Cu alloy. Spectroche111ical analysis on the alloy revealed that the alloy mainly contained 91 % alumi11iu111 and 6% copper. After casting, ho111oge11izatioa1n1n ealing was conducted on IO samples of the alloy at 450°C lix I hou1· and the samples were allowed to cool in the furnace. The homogenized samples were then cold worked to achieve a reduction of 2% in the original length of the samples using a

hydraulic press. Afterwards, 5 ot· the samples were annealed at 250°C; one sa111plew as removed

al'ter 6 minutes. another after 12 111inutes.a nother al'ter 30 minutes, another alter 60 minutes. and

the last aller I 20 minutes. The samples were cooled in air. A similar procedure was carried out 011

the remaining 5 samples at 400°C. Hardness test was conducted on the annealed samples using the

!3rinncl I lardness Testing Machine. Generally, it was discovered that the hardness 01· the alloy

decrcast:s with an increase in annealing time. At the higher temperature (400°C), it was observed

that the hardness value decreased much faster in each of the corresponding time inte1w1ls. This

work provides a basis for the selection of the alloy to 111eedt esired hardness requirements in the industrial applications.